Disclaimer to the On-line Edition
This Manual has been designed for use in the NICU at London Health Sciences Centre (LHSC), London, Ontario, Canada, and represents clinical practice at this institution. The information contained within the Manual may not be applicable to other centres. If users of this Manual are not familiar with a drug, it is recommended that the official monograph be consulted before it is prescribed and administered. Any user of this information is advised that the contributors, Editor and LHSC are not responsible for any errors or omissions, and / or any consequences arising from the use of the information in this Manual.



  • ampicillin is indicated for the treatment of suspected or documented infections caused by susceptible organisms


  • ampicillin is a semi-synthetic penicillin with an extended spectrum; it is bactericidal against the usual penicillin-susceptible Gram-positive organisms (incl. group B streptococcus, Listeria monocytogenes, most strains of enterococci) and many common Gram-negative organisms (incl. Proteus mirabilis, many strains of E. coli, Salmonellae and Shigellae, most strains of Neisseria meningitidis and nonpenicillinase - producing N.gonorrhoeae, many strains of Haemophilus influenzae)
  • ampicillin works similar to other penicillins, ie. inhibition of bacterial cell wall synthesis
  • ampicillin is most often given in combination with an aminoglycoside, partly because of in vitro and animal studies that indicate a synergistic bactericidal effect

Side Effects

  • in adults the major adverse effects associated with ampicillin are hypersensitivity reactions and an "ampicillin rash"; in general, however, ampicillin is very well tolerated by neonates
  • there is the possibility that seizures can occur if serum levels become too high or if the drug is administered too quickly
  • phlebitis has been reported only rarely following IV administration


  • Standard dose: 50 mg/kg IV q12h
  • Meningitis: 100 mg/kg IV q12h
  • For UTI Prophylaxis: 50 mg/kg/day
  • in severe renal dysfunction decrease dose by 50%
  • incompatible with TPN and lipid
  • administer via IV push over 3 to 5 minutes or by slow IV infusion


  • 250 mg vial
  • reconstitute with 5 mL sterile water for injection to produce a final concentration of 50 mg/mL; (this concentration is approximately isotonic) this solution must be used within one hour after reconstitution
  • in volume restricted infants, a concentration of 100 mg/mL may be used after reconstitution
  • (100 mg/mL concentration is to be used for CENTRAL-LINE delivery only)(1)


  1. McEvoy G K (ed): AHFS Drug Information, American Society of Hospital Pharmacists, 1991.
  2. Roberts, RJ: Drug Therapy in Infants, W.B. Saunders, Toronto, 1984.
  3. Trissel L.A.: Handbook on Injectable Drugs, American Society of Hospital Pharmacists 1988.
  4. "AmpicinR" package insert, Bristol Laboratories of Canada, Belleville, Ontario.
  5. Taeusch WH Ballard RA and Avery ME (ed): Schaffer and Avery's Diseases of the Newborn, WB Saunders Co, Toronto, Ontario; 6th Edition, 1991.
  6. Ford DC, Leist ER and Phelps SJ: Guidelines for administration of intravenous medications to pediatric patients, American Society of Hospital Pharmacists, Bethesda, MD, 1988.
  7. Personal Communication. Mr. Larocque, Novapharm Limited, Scarborough, Ontario, ll June 1993.
  8. Phelps SJ: Pediatric Injectable Drugs, 6th Edition, American Society of health-System Pharmacists, Bethesda,MD, 2001.

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